Car Doctor: What's the difference in gasoline between summer and winter?
Q: What is the difference between the gas we buy in the summer and the gas we buy now and through the winter? Does one type get better mileage? Does one store better for use in power equipment?
A: Winter gasoline allows for better cold-weather starting. Due to its formulation, it has less energy, which translates into a bit less fuel economy. In the wintertime, with a little longer warmup time that some people want and the lower energy content of winter fuel, you might see a 5% reduction in fuel economy.
Summer fuel is designed with less evaporative emissions to help eliminate air pollution.
When it comes to storing gas, my suggestion is to use fuel to match the seasons. Your leftover summer gas in a snow blower will work but will start hard when the weather is cold. Winter fuel in summer heat can actually vapor lock and cause stalling. Whatever fuel you use, add a gas stabilizer if the fuel is going to sit for a month or more.
The other option is to purchase ethanol-free fuel. This option is a bit pricey but doesn’t attract moisture as much as the typical pump gas.
Why does Subaru's advance cruise control behave unnaturally?
Q: I have a Subaru with advanced cruise control, and it seems to act unnaturally. There are times that it slows down unexpectedly or other times it hits the brakes (something I should be doing). Is something wrong, or is this just the technology?
A: Advanced cruise control matches the speed of the vehicle in front of you. When that vehicle speeds up, your car will speed up to the preset speed. When that car slows down, your car will slow. When someone cuts in front of you, your car may slow down quickly. These systems generally work best in light to moderate traffic at highway speeds. Even though some will have stop-and-go traffic mode, I find, like you, that the systems don’t feel natural. As good as advanced driver assistance features are today, there is no system that replaces an engaged driver.
What kind of fuel service and tires are recommended for 2014 Chevrolet Cruz?
Q: My 2014 Chevrolet Cruz's mileage is 66,000. Would you recommend an emissions or direct injection fuel service? Also, is it time for tires? Is there a brand that you recommend?
A: Fuel oxidation and volatility concerns can often cause issues with carbon buildup on the valves and combustion chamber. Unless the engine is showing a random misfire code, it is not easy to look for carbon buildup.
If you have a concern about the fuel system, try a high-quality TOP TIER fuel and regular oil changes. For the most up-to-date list of fuel marketers that offer TOP TIER Detergent Gasoline, refer to toptiergas.com.
As for tires, I generally recommend a well-known brand (Michelin, BF Goodrich, Goodyear) for ease of replacement if something comes up, such as a non-repairable puncture.
This year I broke my own rule. I replaced the tires on my car with Nokian tires made in Dayton, Tennessee, and I have been quite happy with the overall performance.
Why did Ford Edge's AC start blowing hot air?
Q: While I was a passenger in the Ford Edge I normally drive, the AC was on and blowing cold air. Suddenly, the passenger side was blowing hot air. I turned it off and then back on, and tried adjusting the temperature, but nothing corrected it. I know it wasn't blowing hot air prior to this day because I definitely would have felt it, as hot as it was.
A: This system, like many, uses a series of motors that adjust temperature by operating blend doors. More than likely, the blend door is stuck, or its motor failed. A technician with a scan tool can go into the body control module and read the codes.
Once the codes are read, they can then determine the cost of the repairs. It could take up to an hour of labor time to determine what is going on.
What's a good model of dashboard camera?
Q: I recall in a past column you discussed dashboard cameras and models you were familiar with. Could you share models you liked?
A: Recently, a neighbor asked me the same question. He was stopped, and a truck backed into him. The truck driver said he hit him – a dash cam would have shown what actually happened.
The brand that I use in my own car is made by Garmin. It can download files onto my phone or from a memory card. The model I have is the 67w, which has some driving features, such as lane-departure warning. The basic models are very discreet. The larger model I have hides neatly behind the rear-view mirror.
John Paul is the AAA Northeast Car Doctor. He has more than 40 years of experience in the automobile industry and is an ASE-Certified Master Technician. Write to John Paul, The Car Doctor, at 110 Royal Little Drive, Providence, RI 02904. Or email jpaul@aaanortheast.com and put “Car Doctor” in the subject field. Follow him on Twitter @johnfpaul or on Facebook.
This article originally appeared on The Providence Journal: Car Doctor: Is there a difference in gas between summer and winter?
